Radio communication method, network side device and user equipment

ABSTRACT

The present disclosure provides a radio communication method, a user equipment, and a network side device, the radio communication method includes: receiving, by a network side device, a random access preamble signal transmitted by a user equipment, where duration of the random access preamble signal is one SC-FDMA symbol or one OFDM symbol, thus air interface overhead of random access can be greatly reduced in a condition that a user equipment can access a cell randomly. The cell may be a microcell or other similar cells.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/CN2013/070480, filed on Jan. 15, 2013, which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to the field of communicationstechnologies and, in particular, to a radio communication method, anetwork side device and a user equipment.

BACKGROUND

With popularization of smart phones and rapid development of mobileinternet technologies, a problem of network capacity and base stationdeployment is becoming more and more serious. Capacity expansion basedon a macro station may render site selection of a base station andengineering construction more and more difficult, and may lead to higherand higher costs, and therefore, miniaturization, low power consumption,controllability and intelligentization of a base station device havealready become a mainstream trend. Hereto, a series of miniaturized basestations, namely small base stations, including a femtocell (Femtocell),a picocell (Picocell) and a microcell (Microcell) and so on, has beenlaunched on the industry chain simultaneously, and all thesetechnologies can be called small cell (Small Cell) technology. A SmallCell is a wireless access point with low power, which may cover a rangeof 10 meters to 200 meters, and being compared with a macro station, acharacteristic of the Small Cell is that it may improve indoor coveragedepth, increase network capacity and lift user experience etc. Indeployment of a long term evolution (Long Term Evolution, LTE for short)system, in order to support more users and higher system capacity, manysmall base stations may be deployed within the coverage of a macro cell.At present, the LTE system is designed aiming at macro cells, andchannels and signals in the system should satisfy the macro coverage.But for the Small Cell, how to provide higher bandwidth, betterperformance and lower costs according to its characteristics is aproblem that needs to be considered urgently.

Any cellular system has a basic requirement that a terminal needs tohave a possibility of applying for establishing a network connection,which is usually referred to as random access. One step in a randomaccess process is that a user equipment (User Equipment, UE for short)transmits a random access preamble (preamble) signal, and a base stationperforms timing estimation based on this signal, thereby realizinguplink synchronization. Duration of the preamble signal relates to acoverage range of a cell, and the bigger the coverage range is, thelonger the duration of the preamble signal gets. In the present LTEsystem, preamble signals are all relatively long, where preamble format0 lasts for about 1 millisecond (ms), supporting coverage up to 14kilometers, preamble format 1 lasts for about 2 ms, supporting coverageup to 77 kilometers, preamble format 2 lasts for about 2 ms, supportingcoverage up to 29 kilometers, and preamble format 3 lasts for about 3ms, supporting coverage up to 100 kilometers. But for a Small Cell,preamble signals of these formats are all relatively long, which is awaste of resources.

SUMMARY

The present disclosure provides a radio communication method, a networkside device and a user equipment, so as to reduce air interface overheadof random access on a premise that a user equipment in a small cell canaccess the small cell randomly.

A first aspect of the present disclosure provides a radio communicationmethod, including:

receiving, by a network side device, a random access preamble signaltransmitted by a user equipment, where duration of the random accesspreamble signal is one single carrier frequency division multiple accessSC-FDMA symbol or one orthogonal frequency division multiplexing OFDMsymbol;

generating, by the network side device, a random access response andtransmitting the random access response to the user equipment.

In a first possible implementation mode of the first aspect, accordingto the first aspect, before the receiving, by a network side device, arandom access preamble signal transmitted by a user equipment, furtherincluding:

transmitting, by the network side device, a signaling to the userequipment, where the signaling is used to indicate that the duration ofthe random access preamble signal currently used by the user equipmentis one SC-FDMA symbol or one OFDM symbol.

In a second possible implementation mode of the first aspect accordingto the first possible implementation mode of the first aspect, thenetwork side device is a base station of a small cell, and/or,

before the transmitting, by the network side device, a signaling to theuser equipment, further including:

determining, by the network side device, that the user equipment doesnot need to execute uplink time synchronization.

In a third possible implementation mode of the first aspect according tothe first aspect, the first possible implementation mode of the firstaspect or the second possible implementation mode of the first aspect,before the receiving, by a network side device, a random access preamblesignal transmitted by a user equipment, further including:

determining, by the network side device, a physical random accesschannel PRACH resource band or resource band pair used to carry therandom access preamble signal of the user equipment;

transmitting, by the network side device, to the user equipment, atransmission period of the PRACH resource band or resource band pair, atransmission offset of the PRACH resource band or resource band pair ineach transmission period, and a frequency domain position of the PRACHresource band or resource band pair.

In a fourth possible implementation of the first aspect according to thethird possible implementation mode of the first aspect, the network sidedevice further transmits one type of following information or anarbitrary combination thereof:

-   -   when bandwidth of the PRACH resource band or resource band pair        is configurable, frequency domain bandwidth of the PRACH        resource band or resource band pair;

when the PRACH resource band or resource band pair supports frequencyhopping, frequency hopping information of the PRACH resource band orresource band pair, where the frequency hopping information includes anyone of or a combination of: information about whether the frequencyhopping is performed on the PRACH resource band or resource band pair,and frequency hopping bandwidth of the PRACH resource band or resourceband pair.

In a fifth possible implementation mode of the first aspect according tothe third or the fourth possible implementation mode of the firstaspect, before the receiving, by a network side device, a random accesspreamble signal transmitted by a user equipment, further including:

transmitting, by the network side device, a signaling to the userequipment, where the signaling is used to indicate a cyclic shiftinterval between two adjacent random access preamble signals which areborne on the PRACH resource band or resource band pair.

In a sixth possible implementation mode of the first aspect according toany one of the third to the fifth possible implementation modes of thefirst aspect, the network side device determines that the PRACH resourceband or resource band pair is not used to carry a physical uplink sharedchannel.

In a seventh possible implementation mode of the first aspect accordingto the first aspect or any one of the first to the sixth possibleimplementation modes of the first aspect, before the receiving, by anetwork side device, a random access preamble signal transmitted by auser equipment, further including:

when determining, by the network side device, that a length of apreamble sequence of the random access preamble signal is 12 or 24,taking a sequence, which is based on quaternary phase shift keying andsearched by a computer, as the preamble sequence of the random accesspreamble signal; when determining that the length of the preamblesequence of the random access preamble signal is greater than or equalto 36, and smaller than or equal to 72, taking a Zadoff-Chu sequence asthe preamble sequence of the random access preamble signal.

In a eighth possible implementation mode of the first aspect accordingto the first aspect or any one of the first to the seventh possibleimplementation modes of the first aspect, before the receiving, by anetwork side device, a random access preamble signal transmitted by auser equipment, further including:

determining, by the network side device, a sequence group number and abase sequence number of the random access preamble signal, where thedetermined sequence group number is consistent with a sequence groupnumber of a sounding reference signal or a physical uplink sharedchannel demodulation reference signal, and the determined base sequencenumber is consistent with a base sequence number of the soundingreference signal or the physical uplink shared channel demodulationreference signal;

transmitting, by the network side device, the determined sequence groupnumber and the determined base sequence number to the user equipment.

In a ninth possible implementation mode of the first aspect according tothe first aspect or any one of the first to the eighth possibleimplementation modes of the first aspect, before the receiving, by anetwork side device, a random access preamble signal transmitted by auser equipment, further including:

determining, by the network side device, a symbol used to carry a PRACHresource band or resource band pair of the random access preamble signalin a subframe, where for a frequency division duplexing system, thesymbol is the last one SC-FDMA symbol or OFDM symbol in an uplinksubframe; or, for a time division duplexing system, the symbol is lastone or last two SC-FDMA symbols or OFDM symbols in an uplink subframe ora special subframe.

In a tenth possible implementation mode of the first aspect according tothe first aspect or any one of the first to the ninth possibleimplementation modes of the first aspect, before the receiving, by anetwork side device, a random access preamble signal transmitted by auser equipment, further including:

determining, by the network side device, that the random access preamblesignal adopts a mapping manner with one subcarrier interval in afrequency domain;

correspondingly, before the receiving, by a network side device, arandom access preamble signal transmitted by a user equipment, furtherincluding: transmitting, by the network side device, a transmission combof the random access preamble signal to the user equipment.

In a eleventh possible implementation mode of the first aspect accordingto the first aspect or any one of the first to the tenth possibleimplementation modes of the first aspect, the random access responsedoes not include timing alignment information.

A second aspect of the present disclosure provides a radio communicationmethod, including:

generating, by a user equipment, a random access preamble signal, whereduration of the random access preamble signal is one single carrierfrequency division multiple access SC-FDMA symbol or one orthogonalfrequency division multiplexing OFDM symbol;

transmitting, by the user equipment, the random access preamble signalto a network side device;

receiving, by the user equipment, a random access response transmittedby the network side device.

In a first possible implementation mode of the second aspect accordingto the second aspect, before the generating, by a user equipment, arandom access preamble signal, further including:

receiving, by the user equipment, a signaling transmitted by the networkside device, where the signaling is used to indicate that the durationof the random access preamble signal currently used by the userequipment is one SC-FDMA symbol or one OFDM symbol;

the generating, by a user equipment, a random access preamble signalincludes:

generating, by the user equipment, the random access preamble signalaccording to the signaling.

In a second possible implementation mode of the second aspect accordingto the first possible implementation mode of the second aspect, the userequipment locates in a small cell;

and/or, the signaling is transmitted after the network side devicedetermines that the user equipment does not need to execute uplink timesynchronization.

In a third possible implementation mode of the second aspect accordingto the second aspect, the first possible implementation mode of thesecond aspect or the second possible implementation mode of the secondaspect, before the transmitting, by the user equipment, the randomaccess preamble signal to a network side device, further including:

receiving, by the user equipment, information about a physical randomaccess channel PRACH resource band or resource band pair used to carrythe random access preamble signal of the user equipment, where theinformation is transmitted by the network side device, and theinformation includes a transmission period of the PRACH resource band orresource band pair, a transmission offset of the PRACH resource band orresource band pair in each transmission period, and a frequency positionof the PRACH resource band or resource band pair;

before the transmitting, by the user equipment, to a network side devicethe random access preamble signal, further including:

determining, by the user equipment, according to the information aboutthe PRACH resource band or resource band pair, a PRACH used to carry therandom access preamble signal of the user equipment.

In a fourth possible implementation mode of the second aspect accordingto the third possible implementation mode of the second aspect, theinformation about the PRACH resource band or resource band pair furtherincludes one type of following information or a combination thereof:

when bandwidth of the PRACH resource band or resource band pair isconfigurable, frequency domain bandwidth of the PRACH resource band orresource band pair;

when the PRACH resource band or resource band pair supports frequencyhopping, frequency hopping information of the PRACH resource band orresource band pair, where the frequency hopping information includes anyone of or a combination of: information about whether the frequencyhopping is performed on the PRACH resource band or resource band pair,and frequency hopping bandwidth of the PRACH resource band or resourceband pair.

In a fifth possible implementation mode of the second aspect accordingto the third or the fourth possible implementation mode of the secondaspect, before the transmitting, by the user equipment, the randomaccess preamble signal to a network side device, further including:

receiving, by the user equipment, a signaling transmitted by the networkside device, where the signaling is used to indicate a cyclic shiftinterval between two adjacent random access preamble signals which areborne on the PRACH resource band or resource band pair;

the generating, by a user equipment, a random access preamble signalincludes:

generating, by the user equipment, the random access preamble signalaccording to the cyclic shift interval.

In a sixth possible implementation mode of the second aspect accordingto the third, the fourth or the fifth possible implementation mode ofthe second aspect, the user equipment does not use the PRACH resourceband or resource band pair to carry a physical uplink shared channel.

In a seventh possible implementation mode of the second aspect accordingto the second aspect or any one of the first to the sixth possibleimplementation modes of the second aspect, before the transmitting, bythe user equipment, the random access preamble signal to a network sidedevice, further including:

when determining, by the user equipment, that a length of a preamblesequence of the random access preamble signal is 12 or 24, taking asequence, which is based on quaternary phase shift keying and searchedby a computer, as the preamble sequence of the random access preamblesignal; when determining that the length of the preamble sequence of therandom access preamble signal is greater than or equal to 36, andsmaller than or equal to 72, taking a Zadoff-Chu sequence as thepreamble sequence of the random access preamble signal.

In a eighth possible implementation mode of the second aspect accordingto the second aspect or any one of the first to the seventh possibleimplementation modes of the second aspect, before the transmitting, bythe user equipment, the random access preamble signal to a network sidedevice, further including:

receiving, by the user equipment, a sequence group number and a basesequence number of the random access preamble signal that aretransmitted by the network side device; where the sequence group numberis consistent with a sequence group number of a sounding referencesignal or a physical uplink shared channel demodulation referencesignal, and the base sequence number is consistent with a base sequencenumber of the sounding reference signal or the physical uplink sharedchannel demodulation reference signal;

the generating, by a user equipment, a random access preamble signalincludes:

generating, by the user equipment, according to the sequence groupnumber and the base sequence number, the random access preamble signal.

In a ninth possible implementation mode of the second aspect accordingto the second aspect or any one of the first to the eighth possibleimplementation modes of the second aspect, before the transmitting, bythe user equipment, the random access preamble signal to a network sidedevice, further including:

determining, by the user equipment, a symbol configured to carry a PRACHresource band or resource band pair of the random access preamble signalin a subframe, where for a frequency division duplexing system, thesymbol is last one SC-FDMA symbol or OFDM symbol in an uplink subframe;or, for a time division duplexing system, the symbol is last one or lasttwo SC-FDMA symbols or OFDM symbols in an uplink subframe or a specialsubframe.

In a tenth possible implementation mode of the second aspect accordingto the second aspect or any one of the first to the ninth possibleimplementation modes of the second aspect, before the transmitting, bythe user equipment, to a network side device the random access preamblesignal, further including:

determining, by the user equipment, that the random access preamblesignal adopts a mapping manner with one subcarrier interval in afrequency domain; and receiving a transmission comb of the random accesspreamble signal transmitted by the network side device;

the transmitting, by the user equipment, the random access preamblesignal to a network side device includes:

transmitting, by the user equipment, the random access preamble signalon a subcarrier indicated by the transmission comb.

In a eleventh possible implementation mode of the second aspectaccording to the second aspect or any one of the first to the tenthpossible implementation modes of the second aspect, the random accessresponse does not include timing alignment information;

after the receiving, by the user equipment, a random access responsetransmitted by the network side device, further including:

performing, by the user equipment, uplink data transmission, and duringthe transmission, according to the random access response, not adjustinga transmission time of the uplink data.

A third aspect of the present disclosure provides a network side device,including:

a receiving module, configured to receive a random access preamblesignal transmitted by a user equipment, where duration of the randomaccess preamble signal is one single carrier frequency division multipleaccess SC-FDMA symbol or one orthogonal frequency division multiplexingOFDM symbol;

a processing module, configured to generate a random access responseaccording to the random access preamble signal received by the receivingmodule;

a transmitting module, configured to transmit the random access responsegenerated by the processing module to the user equipment.

In a first possible implementation mode of the third aspect according tothe third aspect, the processing module is further configured totransmit a signaling to the user equipment via the transmitting module,where the signaling is used to indicate that the duration of the randomaccess preamble signal currently used by the user equipment is oneSC-FDMA symbol or one OFDM symbol.

In a second possible implementation mode of the third aspect accordingto the first possible implementation mode of the third aspect, thenetwork side device is a base station of a small cell, and/or,

the processing module is further configured to, before the transmittingmodule transmits the signaling to the user equipment, determine that theuser equipment does not need to execute uplink time synchronization.

In a third possible implementation mode of the third aspect according tothe third aspect, or the first to the second possible implementationmodes of the third aspect, the processing module is further configuredto determine a physical random access channel PRACH resource band orresource band pair used to carry the random access preamble signal ofthe user equipment;

the transmitting module is further configured to transmit, to the userequipment, a transmission period of the PRACH resource band or resourceband pair, a transmission offset of the PRACH resource band or resourceband pair in each transmission period, and a frequency position of thePRACH resource band or resource band pair.

In a fourth possible implementation mode of the third aspect accordingto the third possible implementation mode of the third aspect, thetransmitting module is further configured to transmit one type offollowing information or an arbitrary combination thereof:

when bandwidth of the PRACH resource band or resource band pair isconfigurable, frequency domain bandwidth of the PRACH resource band orresource band pair;

when the PRACH resource band or resource band pair supports frequencyhopping, frequency hopping information of the PRACH resource band orresource band pair, where the frequency hopping information includes anyone of or a combination of: information about whether the frequencyhopping is performed on the PRACH resource band or resource band pair,and frequency hopping bandwidth of the PRACH resource band or resourceband pair.

In a fifth possible implementation mode of the third aspect according tothe third possible implementation mode of the third aspect or the fourthpossible implementation mode of the third aspect, the transmittingmodule is further configured to transmit a signaling to the userequipment, where the signaling is used to indicate a cyclic shiftinterval between two adjacent random access preamble signals which areborne on the PRACH resource band or resource band pair.

In a sixth possible implementation mode of the third aspect according toany one of the third to the fifth possible implementation modes of thethird aspect, the processing module is further configured to determinethat the PRACH resource band or resource band pair is not used to carrya physical uplink shared channel.

In a seventh possible implementation mode of the third aspect accordingto the third aspect or any one of the first to the sixth possibleimplementation modes of the third aspect, the processing module isfurther configured to, when determining that a length of a preamblesequence of the random access preamble signal is 12 or 24, determinethat the random access preamble signal takes a sequence, which is basedon quaternary phase shift keying and searched by a computer, as thepreamble sequence; when determining that the length of the preamblesequence of the random access preamble signal is greater than or equalto 36, and smaller than or equal to 72, determine that the random accesspreamble signal takes a Zadoff-Chu sequence as the preamble sequence.

In a eighth possible implementation mode of the third aspect accordingto the third aspect or any one of the first to the seventh possibleimplementation modes of the third aspect, the processing module isfurther configured to determine a sequence group number and a basesequence number of the random access preamble signal, where thedetermined sequence group number is consistent with a sequence groupnumber of a sounding reference signal or a physical uplink sharedchannel demodulation reference signal, and the determined base sequencenumber is consistent with a base sequence number of the soundingreference signal or the physical uplink shared channel demodulationreference signal;

the transmitting module is further configured to transmit the sequencegroup number and the base sequence number determined by the processingmodule to the user equipment.

In a ninth possible implementation mode of the third aspect according tothe third aspect or any one of the first to the eighth possibleimplementation modes of the third aspect, the processing module isfurther configured to determine a symbol configured to carry a PRACHresource band or resource band pair of the random access preamble signalin a subframe, where for a frequency division duplexing system, thesymbol is last one SC-FDMA symbol or OFDM symbol in an uplink subframe;or, for a time division duplexing system, the symbol is last one or lasttwo SC-FDMA symbols or OFDM symbols in an uplink subframe or a specialsubframe.

In a tenth possible implementation mode of the third aspect according tothe third aspect or any one of the first to the ninth possibleimplementation modes of the third aspect, the processing module isfurther configured to determine that the random access preamble signaladopts a mapping manner with one subcarrier interval in a frequencydomain, and transmit a transmission comb of the random access preamblesignal to the user equipment via the transmitting module.

In a eleventh possible implementation mode of the third aspect accordingto the third aspect or any one of the first to the tenth possibleimplementation modes of the third aspect, the random access responsetransmitted by the transmitting module does not include timing alignmentinformation.

A fourth aspect of the present disclosure provides a user equipment,including:

a generating module, configured to generate a random access preamblesignal, where duration of the random access preamble signal is onesingle carrier frequency division multiple access SC-FDMA symbol or oneorthogonal frequency division multiplexing OFDM symbol;

a transmitting module, configured to transmit the random access preamblesignal generated by the generating module to a network side device;

a receiving module, configured to, after the transmitting moduletransmits the random access preamble signal, receive a random accessresponse transmitted by the network side device.

In a first possible implementation of the fourth aspect, according tothe fourth aspect, the receiving module is further configured to receivea signaling transmitted by the network side device, where the signalingis used to indicate that the duration of the random access preamblesignal currently used by the user equipment is one SC-FDMA symbol or oneOFDM symbol;

the generating module is further configured to generate the randomaccess preamble signal according to the signaling received by thereceiving module.

In a second possible implementation mode of the fourth aspect accordingto the first possible implementation mode of the fourth aspect, the userequipment locates in a small cell;

and/or, the signaling received by the receiving module is transmittedafter the network side device determines that the user equipment doesnot need to execute uplink time synchronization.

In a third possible implementation mode of the fourth aspect accordingto the fourth aspect, the first possible implementation mode of thefourth aspect or the second possible implementation mode of the fourthaspect, the user equipment further includes a determining module;

the receiving module is further configured to, before the transmittingmodule transmits the random access preamble signal to the network sidedevice, receive information about a physical random access channel PRACHresource band or resource band pair configured to carry the randomaccess preamble signal of the user equipment, where the information istransmitted by the network side device, and the information includes: atransmission period of the PRACH resource band or resource band pair, atransmission offset of the PRACH resource band or resource band pair ineach transmission period, and a frequency domain position of the PRACHresource band or resource band pair;

the determining module is configured to, before the transmitting moduletransmits the random access preamble signal to the network side device,determine, according to the information about the PRACH resource band orresource band pair, a PRACH used to carry the random access preamblesignal of the user equipment;

the transmitting module is specifically configured to transmit therandom access preamble signal generated by the generating module to thenetwork side device on the PRACH determined by the determining module.

In a fourth possible implementation mode of the fourth aspect accordingto the third possible implementation mode of the fourth aspect, theinformation about the PRACH resource band or resource band pair receivedby the receiving module further includes one type of followinginformation or a combination thereof:

when bandwidth of the PRACH resource band or resource band pair isconfigurable, frequency domain bandwidth of the PRACH resource band orresource band pair;

when the PRACH resource band or resource band pair supports frequencyhopping, frequency hopping information of the PRACH resource band orresource band pair, the frequency hopping information includes any oneof or a combination of: information about whether the frequency hoppingis performed on the PRACH resource band or resource band pair, andfrequency hopping bandwidth of the PRACH resource band or resource bandpair.

In a fifth possible implementation mode of the fourth aspect accordingto the third or the fourth possible implementation mode of the fourthaspect, the receiving module is further configured to, before thetransmitting module transmits the random access preamble signal to thenetwork side device, receive a signaling transmitted by the network sidedevice, where the signaling is used to indicate a cyclic shift intervalbetween two adjacent random access preamble signals which are borne onthe PRACH resource band or resource band pair;

the generating module is specifically configured to generate the randomaccess preamble signal according to the cyclic shift interval indicatedby the signaling received by the receiving module.

In a sixth possible implementation mode of the fourth aspect accordingto the fourth aspect or any one of the first to the fifth possibleimplementation modes of the fourth aspect, the user equipment furtherincludes a determining module;

the determining module is configured to, before the transmitting moduletransmits the random access preamble signal to the network side device,when determining that a length of a preamble sequence of the randomaccess preamble signal is 12 or 24, determine that the random accesspreamble signal takes a sequence, which is based on quaternary phaseshift keying and searched by a computer, as the preamble sequence; whendetermining that the length of the preamble sequence of the randomaccess preamble signal is greater than or equal to 36, and smaller thanor equal to 72, determine that the random access preamble signal takes aZadoff-Chu sequence as the preamble sequence.

In a seventh possible implementation mode of the fourth aspect accordingto the fourth aspect or any one of the first to the sixth possibleimplementation modes of the fourth aspect, the receiving module isfurther configured to, before the transmitting module transmits therandom access preamble signal to the network side device, receive asequence group number and a base sequence number of the random accesspreamble signal that are transmitted by the network side device; wherethe sequence group number is consistent with a sequence group number ofa sounding reference signal or a physical uplink shared channeldemodulation reference signal, and the base sequence number isconsistent with a base sequence number of the sounding reference signalor the physical uplink shared channel demodulation reference signal;

the generating module is specifically configured to generate, accordingto the sequence group number received by the receiving module and thebase sequence number received by the receiving module, the random accesspreamble signal.

In an eighth possible implementation mode of the fourth aspect accordingto the fourth aspect or any one of the first to the seventh possibleimplementation modes of the fourth aspect, the user equipment furtherincludes a determining module;

the determining module is configured to determine a symbol configured tocarry a PRACH resource band or resource band pair of the random accesspreamble signal in a subframe, where for a frequency division duplexingsystem, the symbol is last one SC-FDMA symbol or OFDM symbol in anuplink subframe; or, for a time division duplexing system, the symbol islast one or the last two SC-FDMA symbols or OFDM symbols in an uplinksubframe or a special subframe;

the transmitting module is configured to transmit the random accesspreamble signal generated by the generating module to the network sidedevice on the SC-FDMA symbol or the OFDM symbol determined by thedetermining module in the subframe.

In a ninth possible implementation mode of the fourth aspect accordingto the fourth aspect or any one of the first to the eighth possibleimplementation modes of the fourth aspect, the user equipment furtherincludes a determining module;

the determining module is configured to, before the transmitting moduletransmits the random access preamble signal to the network side device,determine that the random access preamble signal adopts a mapping mannerwith one subcarrier interval in a frequency domain;

the receiving module is further configured to receive a transmissioncomb of the random access preamble signal transmitted by the networkside device;

the transmitting module is specifically configured to transmit therandom access preamble signal on a subcarrier indicated by thetransmission comb received by the receiving module.

In a tenth possible implementation mode of the fourth aspect accordingto the fourth aspect or any one of the first to the ninth possibleimplementation modes of the fourth aspect, the random access responsereceived by the receiving module does not include timing alignmentinformation;

the transmitting module is further configured to, after the receivingmodule receives a random access response transmitted by the network sidedevice, perform uplink data transmission, and during the transmission,according to the random access response, not adjust a transmission timeof the uplink data.

A fifth aspect of the present disclosure provides a network side device,including: a transmitter, a receiver, a memory and a processor which iscoupled with the transmitter, the receiver and the memory respectively,where the memory stores a series of program codes, and the processor isconfigured to call the program codes stored in the memory to execute themethod according to the first aspect or any one of the first to theeleventh possible implementation modes of the first aspect.

A sixth aspect of the present disclosure provides a user equipment,including: a transmitter, a receiver, a memory and a processor which iscoupled with the transmitter, the receiver and the memory respectively,where the memory stores a series of program codes, and the processor isconfigured to call the program codes stored in the memory to execute themethod according to the second aspect or any one of the first to theeleventh possible implementation modes of the second aspect.

According to the radio communication method, the network side device andthe user equipment according to the present disclosure, duration of arandom access preamble signal transmitted by a user equipment is onesingle carrier frequency division multiple access (Single-CarrierFrequency Division Multiple Access; SC-FDMA for short) symbol or oneorthogonal frequency division multiplexing (Orthogonal FrequencyDivision Multiplexing; OFDM for short) symbol, thus air interfaceoverhead of random access can be greatly reduced in a condition that auser equipment can access a cell randomly. Where, the cell may be asmall cell or other similar cells.

BRIEF DESCRIPTION OF DRAWINGS

To describe the technical solutions in embodiments of the presentdisclosure or in the prior art more clearly, the following brieflyintroduces the accompanying drawings needed for describing theembodiments or the prior art. Apparently, the accompanying drawings inthe following description illustrate merely some embodiments of thepresent disclosure, and persons of ordinary skill in the art may stillderive other drawings from these accompanying drawings without creativeefforts.

FIG. 1 is a schematic view of an embodiment of a frame structureaccording to the present disclosure;

FIG. 2 is a schematic view of an embodiment of a random access preamblesignal according to the present disclosure;

FIG. 3 is a flowchart of an embodiment of a radio communication methodaccording to the present disclosure;

FIG. 4 is a flowchart of another embodiment of a radio communicationmethod according to the present disclosure;

FIG. 5 is a schematic structural diagram of a network side deviceaccording to another embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of another embodiment of a userequipment according to the present disclosure;

FIG. 7 is a schematic structural diagram of another embodiment of a userequipment according to the present disclosure;

FIG. 8 is a schematic structural diagram of another embodiment of anetwork side device according to the present disclosure; and

FIG. 9 is a schematic structural diagram of still another embodiment ofa user equipment according to the present disclosure.

DESCRIPTION OF EMBODIMENTS

In order to make the purpose, technical solutions and advantages of thepresent disclosure more clear, the technical solution of the presentdisclosure is hereinafter clearly and completely described in detailwith reference to the accompanying drawings. It is evident that theembodiments are only some exemplary embodiments of the presentdisclosure, rather than all embodiments of the present disclosure. Otherembodiments that those skilled in the art obtain based on theembodiments of the present disclosure also fall within the protectionscope of the present disclosure.

In following embodiments of the present disclosure, a network sidedevice refers to a node sending data on a downlink channel, such as abase station. For a device to device (Device to Device; D2D for short)system, the network side device may be a UE, namely a UE sending data toanother UE on the downlink channel.

In order to make the embodiments of the present disclosure more clear, aframe structure in a system is simply introduced here. FIG. 1 is aschematic diagram of an embodiment of a frame structure according to thepresent disclosure. As shown in FIG. 1, a time domain in the system isidentified by a radio frame (Radio Frame), each radio frame includes 10subframes, where the length of a subframe is 1 millisecond (ms), andeach subframe includes 12 or 14 OFDM symbols (symbol), where an uplinksymbol is referred to as an SC-FDMA symbol, and a downlink symbol isreferred to as an OFDM symbol. It should be noted that, if an uplinkmultiple access manner of orthogonal frequency division multiple access(Orthogonal Frequency Division Multiple Access; OFDMA for short) isintroduced in a subsequent technology, an uplink symbol may also becalled as an OFDM symbol. For a Small Cell, typical configuration ofeach subframe is 14 symbols. Each symbol is composed of a cyclic prefix(Cyclic Prefix; CP for short) and a useful symbol. For a frequencydivision duplexing (Frequency Division Duplexing; FDD for short) system,each subframe includes 2 slots (slot). For a time division duplexing(Time Division Duplexing; TDD for short) system, subframe #1 is aspecial subframe (special subframe), subframe 6 is set as a specialsubframe or a downlink subframe according to TDD uplink and downlinkconfiguration. The special subframe is composed of a downlink pilottimeslot (Downlink Pilot TimeSlot; DwPTS for short), a guard period(Guard Period; GP for short) and an uplink pilot timeslot (Uplink PilotTimeSlot; UpPTS for short).

In a Small Cell, a random access may not need to realize uplinksynchronization. A maximum coverage range of the Small Cell is 200meters, and thus a round trip delay (Round Trip Delay; RTD for short) ofa signal is 1.35 microsecond (μs), a downlink synchronization error isusually −1.175 μs to 1.175 μs, so the maximum uncertainty of uplinktiming is 2.525 μs, which is much smaller than duration of the CP. Whenuncertainty time is shorter than the CP, a base station needs not toacquire a timing advance (Timing Advance; TA for short) of each UE, andthereby needs not to perform the uplink synchronization.

When the uplink synchronization is unnecessary, a random access preamble(preamble) signal transmitted by a UE may be simplified to anotification signal, notifying the base station that the UE needs toperform operations such as initial access, wireless connectionre-establishment, requesting an uplink resource or handover etc. Basedon this purpose, a time-frequency domain resource occupied by the randomaccess preamble signal may be reduced. The Small Cell is mentionedabove, for other similar cells, if there is no need to perform theuplink timing or the uplink time synchronization via the random access,then processes for these cells are similar to that for the Small Cell.Description will be made in the following by taking the Small Cell as anexample.

In the present disclosure, a design of a random access preamble signalincludes: a structure of the random access preamble signal.

Specifically, FIG. 2 is a schematic diagram of an embodiment of a randomaccess preamble signal according to the present disclosure. As show inFIG. 2, the random access preamble signal includes two parts which are aCP and a preamble (Preamble). In FIG. 2, T_(CP) identifies duration thatthe CP occupies, T_(SEQ) represents duration that the preamble signaloccupies. The duration of the random access preamble signal is set to beone symbol time, namely one SC-FDMA symbol time or one OFDM symbol time.If the duration of the random access preamble signal is smaller than onesymbol time, an interval between its subcarriers may be bigger thancurrent 15 KHz, in this way, a length of a preamble sequence which canbe supported in certain bandwidth may be reduced, thus the number ofpreamble sequences that can be used may be reduced, and therefore, thenumber of random access users that can be supported on a same resourcemay be reduced. Hence, in the present disclosure, preferably, theduration of the random access preamble signal is one SC-FDMA symbol timeor one OFDM symbol time. Certainly, if the CP is not added into therandom access preamble signal, then the duration of the random accesspreamble signal may be set to be less than one symbol time, and thespecific time may be one symbol time minus the time that the CP needs.

Hereinafter, based on the structure of the designed random accesspreamble signal, a preamble sequence of the random access preamblesignal also can be designed.

Specifically, the preamble sequence may be generated by performing acyclic shift to a base sequence r _(u,v)(n). The base sequences aredivided into 30 groups, which are identified by group numbers (groupnumber) uε{0, 1, . . . , 29}, where v is a base sequence number (basesequence number) in a group. When a length M_(SC) of the preamblesequence is smaller than or equal to 60, there is only one base sequence(namely v=0) in each group; when the length M_(SC) of the preamblesequence is greater than or equal to 72, there are two base sequences(namely v=0,1) in each group.

The aforementioned preamble sequences may be represented by formula (1).

r _(u,v) ^((a))(n)=e ^(jan) r _(u,v)(n),0≦n<M _(SC)  (1)

In the formula (1), r_(u,v) ^((α))(n) is the preamble sequence, r_(u,v)(n) is the base sequence, α is the cyclic shift, and M_(SC) is thelength of the preamble sequence.

Performing cyclic shift to the base sequence is for supporting morepreamble sequences and better orthogonality is achieved among multiplesequences obtained after cyclic shift is performed to a same basesequence. It should be noted that, a linear phase rotation in afrequency domain is equivalent to a cyclic shift in a time domain. Thecyclic shift supported by the random access preamble signal may beconfigured by a higher layer signaling.

For determination of the preamble sequence, when M_(SC) is 12 and 24, aspecial sequence which is based on quaternary phase shift keying(Quadrature Phase Shift Key; QPSK for short) and searched by a computer,may be used as the preamble sequence. When M_(SC) is greater than orequal to 36, and smaller than or equal to 72, a Zadoff-Chu (ZC) sequencemay be used as the preamble sequence. For example, a cyclic extension ofa Zadoff-Chu (ZC) sequence whose length is M_(ZC) may be adopted, here,M_(ZC) is a maximum prime number which is not greater than M_(SC), forexample: when M_(SC)=48, the maximum prime number which is not greaterthan 48 is 47, namely M_(ZC)=47, that is to say, the preamble sequencewith M_(SC) being equal to 48 is obtained by cyclically extending a ZCsequence whose length is 47. Certainly, if M_(SC) is greater than 72, aZC sequence may also be adopted as the preamble sequence.

After determining the preamble sequence, the sequence group number andthe base sequence number of the preamble signal may be determinedfurther.

Where, the sequence group number of the random access preamble signalmay be consistent with a sequence group number of a sounding referencesignal. A sequence group number u at slot n_(s) is determined by a grouphopping pattern f_(gh) (n_(s))) and a sequence shift pattern f_(ss),namely, u=(f_(gh)(n_(s))+f_(ss)) mod 30, where, there are 17 groupfrequency hopping patterns and 30 sequence shift patterns. Whether toenable the group hopping (namely whether f_(gh) (n_(s)) isn't 0) isconfigured by a higher layer signaling. When f_(gh) (n_(s)) is not 0,namely when the group hopping is enabled, the value of f_(gh) (n_(s)) isdetermined according to a cell identifier (Cell Identifier) and changesalong with the slot. When the random access preamble signal follows adesign structure of the sounding reference signal (Sounding ReferenceSignal; SRS for short), f_(ss) is determined according to the cellidentifier, f_(SS)=N_(ID) ^(cell) mod 30, where N_(ID) ^(cell) the cellidentifier. Where, the higher layer signaling (High Layer Signaling) isa signaling coming from a higher layer (layer) and transmitted at alower transmission frequency with respect to a physical layer signaling,and includes a radio resource control (Radio Resource Control; RRC forshort) signaling and a media access control (Media Access Control; MACfor short) signaling and etc.

Or, the sequence group number of the random access preamble signal isset to be consistent with a sequence group number of a physical uplinkshared channel demodulation reference signal (Physical Uplink SharedChannel Demodulation Reference Signal; PUSCH DMRS for short). When therandom access preamble signal follows a design structure of the PUSCHDMRS, f_(ss) is determined according to the cell identifier andΔ_(ss)ε{0, 1, . . . , 29} notified by a higher layer signaling.

The base sequence number of the random access preamble signal may alsobe consistent with a base sequence number of the sounding referencesignal, and is consistent with a base sequence number of the PUSCH DMRS,since the base sequence numbers of the sounding reference signal and thePUSCH DMRS are the same. When M_(SC) is smaller than or equal to 60,there is only one base sequence (namely v=0) in each group; when M_(SC)is greater than or equal to 72, there are two base sequences (namelyv=0,1) in each group. At this time, whether to enable the sequencehopping (Sequence hopping) may be configured by a higher layersignaling. When enabled, v changes between 0 and 1; when disabled, v is0.

The aforementioned setting solution for the sequence group number andthe base sequence number adequately takes into account the problem ofinterferences among the random access preamble signal and other signals.If the sequence group number and the base sequence number are consistentwith those of the sounding reference signal, then it is ensured thatsequences of the random access preamble signal and the soundingreference signal are orthogonal when time-frequency resources of themare the same, thereby ensuring that the interference between the randomaccess preamble signal and the sounding reference signal is the minimum.It is similar to the PUSCH DMRS.

Further, on the basis of having designed the structure of the randomaccess preamble signal, a time-frequency resource of the random accesspreamble signal may also be designed.

A time-frequency resource used for transmitting the random accesspreamble signal is called a physical random access channel (PhysicalRandom Access Channel; PRACH for short). A PRACH resource isdistinguished by a time domain, a frequency domain and a code domain.Multiple PRACH resources with a same time-frequency domainidentification are collectively called a PRACH resource band, themultiple PRACH resources included in one PRACH resource band isdistinguished by the code domain. In the time domain, one PRACH resourceband occupies one SC-FDMA symbol or one OFDM symbol. For a FDD system,the PRACH resource band locates at the last one SC-FDMA symbol or oneOFDM symbol of an uplink subframe. For a TDD system, the PRACH resourceband may not only locate at the last one SC-FDMA symbol or one OFDMsymbol of an uplink subframe, but also may locate at the last one or thelast two SC-FDMA symbols or OFDM symbols of a special subframe. Or, thePRACH resource band may locate at a SC-FDMA symbol or an OFDM symbolwhich can transmit the PUSCH DMRS, namely the fourth SC-FDMA symbol orOFDM symbol in an uplink slot. In the frequency domain, one PRACHresource band occupies N physical resource blocks (Physical ResourceBlock; PRB for short), namely frequency domain bandwidth of the PRACHresource band is N PRBs. N is a positive integer smaller than or equalto 110, and may be notified by a higher layer signaling or bepre-defined in a standard. Preferably, in order to be compatible with aminimum uplink bandwidth, N is a positive integer smaller than or equalto 6. N may also be an integral multiple of 4, namely N=4×M (M is apositive integer smaller than 24), preferably, N is a fixed value 4.

A same design as the aforementioned design of the time-frequencyresource of the random access preamble signal may be also adopted at aUE side, that is, the network side device and the UE may respectivelydetermine the time-frequency resource of the random access preamblesignal. Certainly, the network side device may also notify the UE.

The random access preamble signal may be mapped with one subcarrierinterval, and this needs a transmission comb (Transmission comb) of therandom access preamble signal to be broadcasted via a higher layersignaling, where the transmission comb indicates whether a subcarrierwith an even number or a subcarrier with an odd number is used. TwoPRACH resource bands corresponding to two transmission combs occupying asame PRB may be called a PRACH resource band pair.

When the PRACH resource band locates at the last one SC-FDMA symbol orOFDM symbol of an uplink subframe, in order to avoid a collision betweenthe PRACH and the PUSCH, it is necessary to notify the UE or pre-definethat the PUSCH cannot be transmitted on a time-frequency resource of thePRACH.

In the present disclosure, the design of the PRACH may be morecompatible with existing systems, especially it is not necessary tointroduce a new limitation on PUSCH transmission and a new design on thesize of a PUSCH transmission block.

For the PRACH, a corresponding resource identification can also be set.

Specifically, a PRACH resource is identified by a time domain, afrequency domain and a code domain. A time domain identification (t_id)is a subframe number in a radio frame, where 0≦t_id<10. A frequencydomain identification (f_id) is an identification of the PRACH resourceband or the PRACH resource band pair on a frequency band in a subframe.A frequency domain position in a subframe, of a PRACH resource band or aPRACH resource band pair identified by each f_id, may be configured by abase station and then be notified to the UE, or be pre-defined. Since arandom access radio network temporary identity (Random Access RadioNetwork Temporary Identity; RA-RNTI for short)=1+t_id+10×f_id, while arange of the RA-RNTI is 1 to 60, then in order to be compatible withRA-RNTI values in existing systems, a range of the RA-RNTI in a SmallCell according to the present disclosure is still 0≦f_id<6, f_id and thecode domain identification are identified in an ascending orderaccording to a cyclic shift, where the code domain identification may beregarded as a preamble identification.

For the PRACH, a corresponding power control can be set.

The power control of the PRACH may adopt a mechanism allowing a powerrise. A pathloss (pathloss) and an initial transmission power of thePRACH relate to a sequence length of the PRACH. The PRACH transmissionpower will increase for each unsuccessful random access attempt.

In the following, a method provided by the present disclosure isillustrated by taking the network side device being a base station as anexample.

FIG. 3 is a flowchart of an embodiment of a radio communication methodaccording to the present disclosure As shown in FIG. 3, the radiocommunication method may include:

Step 301. A base station transmits a PRACH parameter to a UE.

Firstly, it should be noted that the base station may not transmit thePRACH parameter to the UE. The base station and the UE may determine thePRACH parameter according to a predefined manner or other manners. Thefollowing mainly describes specific implementation of the base stationtransmitting the PRACH parameter to the UE.

Specifically, before the UE transmits a random access preamble signal,the base station needs to transmit a PRACH parameter to the UE. ThePRACH parameter may include any one or combination of a format of therandom access preamble signal, time-frequency resource information ofthe PRACH, code domain resource information of the PRACH, a step size ofpower increase of the PRACH and a parameter for UE in a non-contentionmechanism.

1) The base station notifies the format of the random access preamblesignal.

The random access preamble signal designed in the present disclosureadopts a new format, which may be named as preamble format 5 (certainlyit is only an example, and is not limited to this name). In existingsystems, there are 4 kinds of preamble formats, plus the format newlydesigned in the present disclosure, there are 5 kinds of preambleformats in total. Hence, the base station needs to configure a preambleformat which is currently used, and notifies the UE via a signaling.Specifically, two methods may be adopted: one method is to use areserved state of an existing PRACH Configuration Index (PRACHConfiguration Index) to indicate the preamble format 5, for example, ina FDD system, at least one of reserved states of the PRACH ConfigurationIndex which are 30, 46, 60, 61 and 62 may be used to indicate thepreamble format 5, and in a FDD system, at least one of the reservedstates of the PRACH Configuration Index which are 58, 59, 60, 61, 62 and63 may be used to indicate the preamble format 5; the other method is touse an additional higher layer signaling to notify the preamble format5.

In the embodiment of the present disclosure, the duration of the randomaccess preamble signal is limited within one symbol time, i.e., withinone SC-FDMA symbol or one OFDM symbol.

2) The base station notifies the time-frequency resource information ofthe PRACH.

In each subframe, L PRACH resource band(s) may be configured, where L isan integer greater than or equal to 0. The base station may configure atime-frequency position of the PRACH resource band or resource band pairvia a higher layer signaling, where content of the signaling includesinformation such as a transmission period of the PRACH resource band orresource band pair and a transmission offset (offset) in eachtransmission period; and a frequency domain position (i.e. a startingpoint in the frequency domain) of the PRACH resource band or resourceband pair. Where the transmission period of the PRACH resource band orresource band pair and the transmission offset (offset) in eachtransmission period may adopt a transmission period and a transmissionoffset defined by SRS, or may also adopt a transmission period and atransmission offset defined by an existing PRACH.

The content of the signaling may also include any one or a combinationof the followings: when bandwidth of the PRACH is configurable,frequency domain bandwidth of the PRACH resource band or resource bandpair; when the PRACH resource band or resource band pair supportsfrequency hopping, frequency hopping information of the PRACH resourceband or resource band pair notified by the base station, where thefrequency hopping information includes information about whether thefrequency hopping is performed on the PRACH resource band or resourceband pair, and frequency hopping bandwidth of the PRACH resource band orresource band pair.

Besides, in order to save overhead, a reserve state of the existingPRACH Configuration Index may be adopted to notify the time-frequencyresource information of the PRACH.

3) The base station notifies the code domain information of the PRACH.

Multiple PRACH resources included in one PRACH resource band isdistinguished via the code domain. Preferably, different code resourcesare generated after performing different cyclic shifts to a same basesequence. The different code domain resources corresponding to a PRACHresource band may be configured via a higher layer signaling. For aSmall Cell, J preamble sequences (where J is a positive integer) aresupported on each PRACH resource band, the preamble sequences aregenerated by cyclically shifting the base sequence, J=└M_(SC)/N_(CS)┘,where └ ┘ represents rounding down, M_(SC) is the length of the preamblesequence, N_(CS) is used to indicate a cyclic shift interval, and thiscyclic shift interval is a cyclic shift interval between two adjacentpreamble sequences which are generated from a same base sequence.Therefore, the cyclic shift

$\alpha = \{ {\begin{matrix}\frac{v \cdot N_{CS}}{M_{SC}} & {{v = 0},1,\ldots \mspace{14mu},{\lfloor {M_{SC}\text{/}N_{CS}} \rfloor - 1},{N_{CS} \neq 0}} \\0 & {N_{CS} = 0}\end{matrix}.} $

Hence, the base station may notify the UE of the code domain resourceinformation on a PRACH resource band via N_(CS).

4) The base station notifies the step size of the power increase of thePRACH.

Specifically, the base station may notify the UE of the step size of thetransmission power increase of the PRACH via a higher layer signaling.

5) The base station notifies the parameter for UE in the non-contentionmechanism.

The random access is divided into a contention based random access(contention based random access) and a non-contention based randomaccess (non-contention based random access). For the non-contentionbased random access, the base station allocates a dedicated randomaccess preamble signal to the UE. The base station may allocate thededicated random access preamble signal to the UE via a physicaldownlink control channel order (Physical Downlink Control Channel order;PDCCH order for short). At present, there are 64 preamble sequencesavailable in each cell, so 6-bit information in the PDCCH order is usedfor indicating a preamble index/identifier (preamble index/identifier),the preamble sequences in the Small Cell may be reduced subsequently,and thereby there may be redundant bits and these redundant bits mayfurther indicate the time-frequency resource of the PRACH.

Besides, in order to avoid a collision between the PRACH and the PUSCH,it is necessary to notify the UE or pre-define that the PUSCH cannot betransmitted on a time-frequency resource of the PRACH.

Step 302. The base station receives a random access preamble signaltransmitted by the UE.

In this embodiment, duration of the above random access preamble signalis one SC-FDMA symbol or one OFDM symbol.

The random access preamble signal transmitted by the UE may be generatedbased on the aforementioned design of the random access preamble signal,which will not be repeated here.

Step 303. The base station generates a random access response, andtransmits the random access response to the UE.

In order to respond to a detected random access attempt, the basestation generates the random access response (Random Access Response),and transmits the random access response to the UE. The random accessresponse includes a random access preamble identification detected by anetwork, and responds that this sequence is valid. The random accessresponse is PDCCH scheduling that is scrambled by an RA-RNTI. TheRA-RNTI can identify time domain and frequency domain information fortransmitting the random access preamble signal.

Since it is not necessary for the Small Cell to perform uplinksynchronization, therefore the random access response may not includetiming alignment information (Timing Alignment information), and therebysignaling overhead can be saved.

In the aforementioned embodiment, the duration of the random accesspreamble signal transmitted by the UE is one SC-FDMA symbol or one OFDMsymbol, and thus air interface overhead of random access can be greatlyreduced on a premise that a UE in a small cell (Small Cell) can accessthe small cell randomly. Besides, the design of the PRACH may be morecompatible with the existing system, and especially, it is not necessaryto introduce a new limitation on PUSCH transmission and a new design onthe size of a PUSCH transmission block.

FIG. 4 is a flowchart of another embodiment of a radio communicationmethod according to the present disclosure. As shown in FIG. 4, theradio communication method may include:

Step 401. A UE receives a PRACH parameter transmitted by a base station.

Specifically, before the UE transmits a random access preamble signal,the UE needs to receive the PRACH parameter sent by the base station.The PRACH parameter may include one of or a combination of a format ofthe random access preamble signal, time-frequency resource informationof the PRACH, code domain resource information of the PRACH, a step sizeof power increase of the PRACH and a UE parameter in a non-contentionmechanism.

It should be noted that since the method flow at the UE side relates tothe method flow at the base station side, except that the base stationside is a transmitting end of the PRACH parameter while the UE is areceiving end of the PRACH parameter, thus for detailed descriptionsabout the PRACH parameter, introductions in the embodiment as shown inFIG. 3 according to the present disclosure may be referred to. Only asimple description of each parameter is included here.

In these PRACH parameters, the format of the random access preamblesignal is: duration of a currently used random access preamble signalbeing one SC-FDMA symbol or one OFDM symbol. Moreover, the format may betransmitted to the UE after the base station determines that the UE doesnot need to execute uplink time synchronization.

The aforementioned time-frequency resource information of the PRACHincludes: a transmission period of a PRACH resource band or resourceband pair, a transmission offset of the PRACH resource band or resourceband pair in each transmission period, and a frequency domain positionof the PRACH resource band or resource band pair. The time-frequencyresource information of the PRACH may further include: when bandwidth ofthe PRACH resource band or resource band pair is configurable, frequencydomain bandwidth of the PRACH resource band or resource band pair; whenthe PRACH resource band or resource band pair supports frequencyhopping, frequency hopping information of the PRACH resource band orresource band pair, where the frequency hopping information includes anyone or combination of the followings: information about whether thefrequency hopping is performed on the PRACH resource band or resourceband pair, and frequency hopping bandwidth of the PRACH resource band orresource band pair.

The code domain resource information of the PRACH includes: informationto indicate a cyclic shift interval between two adjacent random accesspreamble signals which are carried on the PRACH resource band orresource band pair.

Certainly, the UE may not receive the parameter, but determines theabove parameter according to a predefined manner or other manners.

For example, as for the duration of the random access preamble signal,the UE may determine the format of the random access preamble signal ina pre-defined manner, i.e., determining that the length of the randomaccess preamble signal is one SC-FDMA symbol or one OFDM symbol.

The UE may also determine the code domain resource information of thePRACH of the random access preamble signal in a pre-defined manner, forexample, determining a manner for generating a preamble sequence.Specifically, when determining that a length of the preamble sequence ofthe random access preamble signal is 12 or 24, the UE may use a sequencewhich is based on quaternary phase shift keying and searched by acomputer, as the aforementioned preamble sequence of the random accesspreamble signal; when determining that the length of the preamblesequence of the random access preamble signal is greater than or equalto 36, and smaller than or equal to 72, use a Zadoff-Chu sequence as thepreamble sequence of the random access preamble signal.

The UE may also determine the time-frequency resource information of thePRACH of the random access preamble signal in a pre-defined manner, forexample, determining a symbol used to carry a PRACH resource band orresource band pair of the random access preamble signal in a subframe,and for a frequency division duplexing system, the symbol is the lastone SC-FDMA symbol or OFDM symbol in an uplink subframe; or, for a timedivision duplexing system, the symbol is the last one or the last twoSC-FDMA symbols or OFDM symbols in an uplink subframe or a specialsubframe.

The UE may also determine other time-frequency resource information ofthe PRACH of the random access preamble signal in a pre-defined manner,for example, determining that the random access preamble signal adopts amapping manner with one subcarrier interval in a frequency domain.However, in this case, the UE needs a network device to provide atransmission comb of the random access preamble signal, so that the UEmay transmit the random access preamble signal on a subcarrier indicatedby the transmission comb.

Step 402. Based on the received parameter, the UE generates the randomaccess preamble signal, and transmits the generated random accesspreamble signal to the base station.

If the received PRACH parameter includes the format of the random accesspreamble signal, then the UE generates, according to the format, therandom access preamble signal the duration of which is one SC-FDMAsymbol or one OFDM symbol.

If the received PRACH parameter includes the time-frequency resourceinformation of the PRACH, then the UE determines, according to theinformation, the PRACH used for carrying the random access preamblesignal of the UE. Specifically, for a FDD system, the random accesspreamble signal generated by the UE may be transmitted on the last oneSC-FDMA symbol or OFDM symbol in an uplink subframe, or, for a TDDsystem, the random access preamble signal generated by the UE may betransmitted on the last one or the last two SC-FDMA symbols or OFDMsymbols in an uplink subframe or a special subframe. Or, the UE also maytransmit the random access preamble signal on a SC-FDMA symbol or anOFDM symbol on which a PUSCH DMRS can be transmitted.

If the received PRACH parameter includes the code domain resourceinformation of the PRACH, then the UE generates the random accesspreamble signal according to a cyclic shift interval of the code domainresource information.

If the received PRACH parameter includes a sequence group number and abase sequence number of the random access preamble signal, then the UEgenerates the random access preamble signal according to the sequencegroup number and the base sequence number.

Certainly, if there are multiple parameters, the UE may generate therandom access preamble signal with an overall consideration of theseparameters, and transmits the random access preamble signal.

As previously mentioned, for generating the random access preamblesignal by the UE, the UE may not need to receive a parameter, butgenerates and transmits the random access preamble signal according to apre-defined design.

For example, in a pre-defined manner, if the UE can determine the formatof the random access preamble signal, then can generate the randomaccess preamble signal according to the format; if the UE can determinethe preamble sequence of the random access preamble signal, then cangenerate the random access preamble signal according to the preamblesequence; if the UE can determine the code domain resource informationof the PRACH of the random access preamble signal, then can generate therandom access preamble signal according to the cyclic shift interval inthe code domain resource information; if the UE can determine thetime-frequency resource information of the PRACH of the random accesspreamble signal, then the UE can determine, according to theinformation, the PRACH used for carrying the random access preamblesignal of the UE.

Besides, if the UE can determine other time-frequency resourceinformation of the PRACH of the random access preamble signal in apre-defined manner, for example, determining that the random accesspreamble signal adopts a mapping manner with one subcarrier interval ina frequency domain, for this manner, the UE needs to acquire atransmission comb of the random access preamble signal from the basestation, then, when transmitting the random access preamble signal, theUE may transmit on a subcarrier indicated by the transmission comb.

Step 403. The UE receives a random access response transmitted by thebase station.

In order to determine whether the base station receives the randomaccess preamble signal transmitted by the UE, the UE needs to monitorand receive the random access response. Before acquiring the randomaccess response, the UE needs to detect a PDCCH scrambled by a RA-RNTIat first, then acquires scheduling information of the random accessresponse via the PDCCH, thereby acquiring the random access response.

Besides, the random access response transmitted by the base station doesnot include timing alignment information; correspondingly, whenperforming uplink data transmission, according to the random accessresponse, the UE does not adjust a transmission time of the uplink data.

Moreover, in order to avoid a collision between the PRACH and the PUSCH,the UE should not use the PRACH resource band or resource band pair tocarry and transmit the PUSCH. As previously mentioned, it may benotified to the UE by the base station, or may be pre-defined.

In the aforementioned embodiment, the duration of the random accesspreamble signal transmitted by the UE is one SC-FDMA symbol or one OFDMsymbol, thus air interface overhead of random access can be greatlyreduced on a premise that a UE in a small cell (Small Cell) can accessthe small cell randomly. Besides, the design of the PRACH may be morecompatible with existing systems, and especially, it is not necessary tointroduce a new limitation on PUSCH transmission and a new design on thesize of a PUSCH transmission block.

Persons of ordinary skill in the art may understand that all or part ofthe steps in the above method embodiments may be implemented by aprogram instructing relevant hardware. The program may be stored in acomputer readable storage medium. When the program is executed, theforegoing steps in the method embodiments are performed. Theaforementioned storage medium includes any medium capable of storingprogram codes, such as a ROM, a RAM, a magnetic disk, or an opticaldisk.

FIG. 5 is a schematic structural diagram of an embodiment of a networkside device according to the present disclosure. The network side devicein this embodiment may implement the flow of the embodiment as shown inFIG. 3 of the present disclosure. As shown in FIG. 5, the network sidedevice may include: a receiving module 51, a transmitting module 52 anda processing module 53.

The receiving module 51 is configured to receive a random accesspreamble signal transmitted by a UE, where duration of the random accesspreamble signal is one SC-FDMA symbol or one OFDM symbol.

The processing module 53 is configured to generate a random accessresponse according to the random access preamble signal received by thereceiving module 51.

The transmitting module 52 is configured to transmit the random accessresponse generated by the processing module 53 to the UE.

In this embodiment, the processing module 53 is further configured totransmit a signaling to the UE via the transmitting module 52, where thesignaling is used to indicate that the duration of the random accesspreamble signal currently used by the UE is one SC-FDMA symbol or oneOFDM symbol. In this way, the UE may generate the random access preamblesignal according to the signaling after receiving the signaling.

In this embodiment, the aforementioned network side device may be a basestation of a small cell, and/or,

the processing module 53 is further configured to, before transmitting,via the transmitting module 52, the signaling to the UE, determine thatthe UE does not need to execute uplink time synchronization. That is tosay, after determining that the UE does not need to execute the uplinktime synchronization, the processing module 53 transmits theaforementioned signaling to the UE via the transmitting module 52.

In this embodiment, the processing module 53 is further configured todetermine a PRACH resource band or resource band pair used to carry therandom access preamble signal of the UE;

the transmitting module 52 is further configured to transmit atransmission period of the PRACH resource band or resource band pair, atransmission offset of the PRACH resource band or resource band pair ineach of the transmission period and a frequency domain position of thePRACH resource band or resource band pair, to the UE.

Further, on the basis of transmitting the transmission period of thePRACH resource band or resource band pair, the transmission offset ofthe PRACH resource band or resource band pair in each of thetransmission period, and the frequency domain position of the PRACHresource band or resource band pair, the transmitting module 52 is alsoconfigured to transmit one type or any combination of followinginformation:

when bandwidth of the PRACH resource band or resource band pair isconfigurable, frequency domain bandwidth of the PRACH resource band orresource band pair;

when the PRACH resource band or resource band pair supports frequencyhopping, frequency hopping information of the PRACH resource band orresource band pair, where the frequency hopping information includes anyone of or a combination of: information about whether the frequencyhopping is performed on the PRACH resource band or resource band pair,and frequency hopping bandwidth of the PRACH resource band or resourceband pair.

Further, the transmitting module 52 is also configured to transmit asignaling to the UE, where the signaling is used to indicate a cyclicshift interval between two adjacent random access preamble signals whichare borne on the PRACH resource band or resource band pair. In this way,after receiving the signaling, the UE may generate the random accesspreamble signal according to the cyclic shift interval.

Further, in order to avoid a collision between the PRACH and the PUSCH,the processing module 53 is also configured to determine that the PRACHresource band or resource band pair is not used to carry the PUSCH, thenthe transmitting module 52 may also notify the UE that the PRACHresource band or resource band pair is not used to carry the PUSCH,certainly, that the PUSCH cannot be transmitted on the time-frequencyresource of the PRACH may also be pre-defined; in this way, the UE willnot use the PRACH resource band or resource band pair to carry thePUSCH.

In this embodiment, the processing module 53 is further configured to,when determining that a length of a preamble sequence of the randomaccess preamble signal is 12 or 24, determine that the random accesspreamble signal takes a sequence which is based on quaternary phaseshift keying and searched by a computer, as the preamble sequence; whendetermining that the length of the preamble sequence of the randomaccess preamble signal is greater than or equal to 36, and smaller thanor equal to 72, determine that the random access preamble signal takes aZadoff-Chu sequence as the preamble sequence.

In this embodiment, the processing module 53 is further configured todetermine a sequence group number and a base sequence number of therandom access preamble signal, where the determined sequence groupnumber is consistent with a sequence group number of a SRS or a PUSCHDMRS, the determined base sequence number is consistent with a basesequence number of the SRS or the PUSCH DMRS; then the transmittingmodule 52 is further configured to transmit the sequence group numberand the base sequence number determined by the processing module 53 tothe UE. In this way, the UE may generate the random access preamblesignal according to the sequence group number and the base sequencenumber. The aforementioned setting solution for the sequence groupnumber and the base sequence number adequately takes into account theproblem of interferences among the random access preamble signal andother signals. If the sequence group number and the base sequence numberare consistent with those of SRS, then it can be ensured that whentime-frequency resources of the random access preamble signal and theSRS are the same, sequences of them can be orthogonal, thereby ensuringthat the interference between the random access preamble signal and theSRS is the minimum. It is similar to the PUSCH DMRS.

In this embodiment, the processing module 53 is further configured todetermine a symbol used to carry a PRACH resource band or resource bandpair of the random access preamble signal in a subframe, and for a FDDsystem, the symbol is the last one SC-FDMA symbol or OFDM symbol in anuplink subframe; or, for a TDD system, the symbol is the last one or thelast two SC-FDMA symbols or OFDM symbols in an uplink subframe or aspecial subframe.

In this embodiment, the processing module 53 is further configured todetermine that the random access preamble signal adopts a mapping mannerwith one subcarrier interval in a frequency domain, and transmit atransmission comb of the random access preamble signal to the UE via thetransmitting module 52. In this way, the UE may transmit the randomaccess preamble signal on a subcarrier indicated by the transmissioncomb.

In this embodiment, the random access response transmitted by thetransmitting module 52 does not include timing alignment information. Inthis way, after receiving the random access response, according to therandom access response, the UE will not adjust a transmission time ofthe uplink data in a process of performing uplink data transmission.

In hardware implementation, the aforementioned transmitting module 52may be a transmitter or a transceiver, the aforementioned receivingmodule 51 may be a receiver or a transceiver, and the transmittingmodule 52 and the receiving module 51 may be integrated together to forma transceiving unit, which corresponds to a transceiver in hardwareimplementation. The aforementioned processing module 53 may be embeddedinto or separated from a processor of the network side device in theform of hardware, it may also be stored into a memory of the networkside device in the form of software, so that the processor calls andexecutes operations corresponding to the aforementioned modules. Thisprocessor may be a central processing unit (CPU), a microprocessor or asingle chip microcomputer and etc.

In this embodiment, the network side device refers to a node sendingdata on a downlink channel, such as a base station. For a D2D system,the network side device may be a UE, namely, a UE sending data toanother UE on a downlink channel.

In the aforementioned embodiment, the duration of the random accesspreamble signal transmitted by the UE is one SC-FDMA symbol or one OFDMsymbol, thus air interface overhead of random access can be greatlyreduced on a premise that a UE in a small cell (Small Cell) can accessthe small cell randomly. Besides, the design of the PRACH may be morecompatible with existing system, and, especially, it is not necessary tointroduce a new limitation on PUSCH transmission and a new design on thesize of a PUSCH transmission block.

FIG. 6 is a schematic structural diagram of a user equipment accordingto another embodiment of the present disclosure, the UE in thisembodiment may implement the flow of the embodiment shown in FIG. 4according to the present disclosure. As shown in FIG. 6, the UE mayinclude: a generating module 61, a transmitting module 62 and areceiving module 63.

The generating module 61 is configured to generate a random accesspreamble signal, where duration of the random access preamble signal isone SC-FDMA symbol or one OFDM symbol; specifically, the generatingmodule 61 may generate the random access preamble signal based on theaforementioned design of the random access preamble signal.

The transmitting module 62 is configured to transmit the random accesspreamble signal generated by the generating module 61 to a network sidedevice.

The receiving module 63 is configured to, after the transmitting module62 transmits the random access preamble signal, receive a random accessresponse transmitted by the network side device.

In hardware implementation, the aforementioned transmitting module 62may be a transmitter or a transceiver, the aforementioned receivingmodule 63 may be a receiver or a transceiver, and the transmittingmodule 62 and the receiving module 63 may be integrated together to forma transceiving unit, which corresponds to a transceiver in hardwareimplementation. The aforementioned generating module 61 may be embeddedinto or separated from a processor of the UE in the form of hardware, itmay also be stored into a memory of the UE in the form of software, sothat the processor calls and executes operations corresponding to theaforementioned modules. This processor may be a central processing unit(CPU), a microprocessor or a single chip microcomputer and etc.

In the aforementioned embodiment, the duration of the random accesspreamble signal transmitted by the UE is one SC-FDMA symbol or one OFDMsymbol, thus air interface overhead of random access can be greatlyreduced on a premise that a UE in a small cell (Small Cell) can accessthe small cell randomly. Besides, the design of the PRACH may be morecompatible with existing systems, and especially, it is not necessary tointroduce a new limitation on PUSCH transmission and a new design on thesize of a PUSCH transmission block.

FIG. 7 is a schematic structural diagram of another embodiment of a userequipment according to the present disclosure. Being compared with theUE shown in FIG. 6, the difference is that, in the UE shown in FIG. 7,the receiving module 63 is further configured to receive a signalingtransmitted by the network side device, where the signaling is used toindicate that the duration of the random access preamble signalcurrently used by the user equipment is one SC-FDMA symbol or one OFDMsymbol; at this time, the generating module 61 is further configured togenerate the random access preamble signal according to the signalingreceived by the receiving module 63.

In this embodiment, the UE may locate in a small cell; and/or, thesignaling received by the receiving module 63 is transmitted after thenetwork side device determines that the UE does not need to executeuplink time synchronization.

Further, the UE may also include: a determining module 64;

the receiving module 63 is further configured to, before thetransmitting module 62 transmits the random access preamble signal tothe network side device, receive information about a PRACH resource bandor resource band pair used to carry the random access preamble signal ofthe UE, where the information is sent by the network side device, andthe information includes a transmission period of the PRACH resourceband or resource band pair, a transmission offset of the PRACH resourceband or resource band pair in each transmission period, and a frequencydomain position of the PRACH resource band or resource band pair; inthis way, before the transmitting module 62 transmits the random accesspreamble signal to the network side device, the determining module 64may determine, according to the information about the PRACH resourceband or resource band pair, a PRACH used to carry the random accesspreamble signal of the UE. Correspondingly, the transmitting module 62is specifically configured to transmit the random access preamble signalgenerated by the generating module 61 on the PRACH determined by thedetermining module 64 to the network side device.

Further, the information about the PRACH resource band or resource bandpair received by the receiving module 63 may also include one type offollowing information or a combination thereof: when bandwidth of thePRACH resource band or resource band pair is configurable, frequencydomain bandwidth of the PRACH resource band or resource band pair; whenthe PRACH resource band or resource band pair supports frequencyhopping, frequency hopping information of the PRACH resource band orresource band pair, where the aforementioned frequency hoppinginformation includes any one of or a combination of: information aboutwhether the frequency hopping is performed on the PRACH resource band orresource band pair, and frequency hopping bandwidth of the PRACHresource band or resource band pair.

Further, the receiving module 63 is further configured to, before thetransmitting module 62 transmits the random access preamble signal tothe network side device, receive a signaling transmitted by the networkside device, where the signaling is used to indicate a cyclic shiftinterval between two adjacent random access preamble signals which areborne on the PRACH resource band or resource band pair; at this time,the generating module 61 is specifically configured to generate therandom access preamble signal according to the cyclic shift intervalindicated by the signaling received by the receiving module 63.

Certainly, the UE may not receive the signaling and/or the informationof the PRACH resource band or resource band pair transmitted by thenetwork side device, but determine a parameter which is necessary forgenerating the random access preamble signal according to a pre-definedmanner or other manners.

For example, for the duration of the random access preamble signal, thedetermining module 64 may determine the format of the random accesspreamble signal in a pre-defined manner, i.e., determining that thelength of the random access preamble signal is one SC-FDMA symbol or oneOFDM symbol.

The determining module 64 may also determine the code domain resourceinformation of the PRACH of the random access preamble signal in apre-defined manner, for example, determining a manner for generating apreamble sequence. Specifically, before the transmitting module 62transmits the random access preamble signal to a network side device,when determining that a length of a preamble sequence of the randomaccess preamble signal is 12 or 24, the determining module 64 maydetermine that the random access preamble signal takes a sequence, whichis based on quaternary phase shift keying and searched by a computer, asthe preamble sequence; when determining that the length of the preamblesequence of the random access preamble signal is greater than or equalto 36, and smaller than or equal to 72, the determining module 64 maydetermine that the random access preamble signal takes a Zadoff-Chusequence as the preamble sequence.

Besides, the determining module 64 may determine the time-frequencyresource information of the PRACH of the random access preamble signalin a pre-defined manner, for example, determining a symbol used to carrythe PRACH resource band or resource band pair of the random accesspreamble signal in a subframe, and for a frequency division duplexingsystem, the symbol is the last one SC-FDMA symbol or OFDM symbol in anuplink subframe; or, for a time division duplexing system, the symbol isthe last one or the last two SC-FDMA symbols or OFDM symbols in anuplink subframe or a special subframe. At this time, the transmittingmodule 62 may transmit the random access preamble signal generated bythe generating module 61 to the network side device on the SC-FDMAsymbol or the OFDM symbol determined by the determining module 64 in thesubframe.

The determining module 64 may also determine other time-frequencyresource information of the PRACH of the random access preamble signalin a pre-defined manner, for example, determining that the random accesspreamble signal adopts a mapping manner with one subcarrier interval ina frequency domain. However, in this case, the receiving module 63 needsto receive a transmission comb of the random access preamble signal,where the transmission comb is sent by the network device, and then thetransmitting module 62 may transmit the random access preamble signal ona subcarrier indicated by the transmission comb received by thereceiving module 63.

Further, in this embodiment, the receiving module 63 is also configuredto, before the transmitting module 62 transmits the random accesspreamble signal to a network side device, receive a sequence groupnumber and a base sequence number of the random access preamble signaltransmitted by the network side device; where, the sequence group numberis consistent with a sequence group number of an SRS or a PUSCH DMRS,the base sequence number is consistent with a base sequence number ofthe SRS or the PUSCH DMRS. At this time, the generating module 61 isspecifically configured to generate, according to the sequence groupnumber received by the receiving module 63 and the base sequence numberreceived by the receiving module 63, the random access preamble signal.

In this embodiment, the random access response received by the receivingmodule 63 does not include timing alignment information. Further, thetransmitting module 62 is also configured to, after the receiving module63 receives the random access response transmitted by the network sidedevice, perform uplink data transmission, and during a process of thetransmission and according to the random access response, do not adjusta transmission time of the uplink data.

In this embodiment, if the receiving module 63 receives a signalingwhich is transmitted by the network side device and indicates that theduration of the random access preamble signal currently used by the UEis one SC-FDMA symbol or one OFDM symbol, then the generating module 61may generate, according to the signaling, a random access preamblesignal, duration of which is one SC-FDMA symbol or one OFDM symbol.

If the receiving module 63 receives information about the PRACH resourceband or resource band pair, then the determining module 64 determines,according to the information, the PRACH used for carrying the randomaccess preamble signal of the UE. Specifically, for a FDD system, therandom access preamble signal generated by the generating module 61 maybe transmitted on the last one SC-FDMA symbol or OFDM symbol in anuplink subframe, or, for a TDD system, the random access preamble signalgenerated by the generating module 61 may be transmitted on the last oneor the last two SC-FDMA symbols or OFDM symbols in an uplink subframe ora special subframe. Or, the transmitting module 62 also may transmit theaforementioned random access preamble signal on a SC-FDMA symbol or anOFDM symbol that can transmit the PUSCH DMRS.

If the receiving module 63 receives a signaling used to indicate acyclic shift interval between two adjacent random access preamblesignals which are borne on the PRACH resource band or resource bandpair, then the generating module 61 may generate the random accesspreamble signal according to the aforementioned cyclic shift interval.

If the receiving module 63 receives a sequence group number and a basesequence number of the random access preamble signal, then thegenerating module 61 may generate the random access preamble signalaccording to the sequence group number and the base sequence number.

Certainly, if the receiving module 63 receives a plurality of signalingsand/or parameters, then the generating module 61 may generate the randomaccess preamble signal with an overall consideration of these signalingsand/or parameters, and the transmitting module 62 also may transmit therandom access preamble signal with an overall consideration of thesesignalings and/or parameters.

As previously mentioned, for generating the random access preamblesignal, the generating module 61 may not need to receive signalingsand/or parameters, but generate the random access preamble signalaccording to a pre-defined design.

For example, in a pre-defined manner, if the determining module 64 candetermine a format of the random access preamble signal, then thegenerating module 61 may generate the random access preamble signalaccording to the format; if the determining module 64 can determine apreamble sequence of the random access preamble signal, then thegenerating module 61 may generate the random access preamble signalaccording to the preamble sequence; if the determining module 64 candetermine code domain resource information of the PRACH of the randomaccess preamble signal, then the generating module 61 may generate therandom access preamble signal according to a cyclic shift interval inthe code domain resource information; if the determining module 64 candetermine the time-frequency resource information of the PRACH of therandom access preamble signal, then a PRACH used for carrying the randomaccess preamble signal of the UE may be determined according to theinformation.

Besides, in order to avoid a collision between the PRACH and the PUSCH,the UE should not use the PRACH resource band or resource band pair tocarry and transmit the PUSCH. As previously mentioned, it may benotified to the UE by the base station, or may be pre-defined.

In hardware implementation, the aforementioned transmitting module 62may be a transmitter or a transceiver, the aforementioned receivingmodule 63 may be a receiver or a transceiver, and the transmittingmodule 62 and the receiving module 63 may be integrated together to forma transceiving unit, which corresponds to a transceiver in hardwareimplementation. The aforementioned generating module 61 and thedetermining module 64 may be embedded into or separated from a processorof the UE in the form of hardware, it may also be stored into a memoryof the UE in the form of software, so that the processor calls andexecutes operations corresponding to the aforementioned modules. Thisprocessor may be a central processing unit (CPU), a microprocessor or asingle chip microcomputer and etc.

In the aforementioned embodiment, the duration of the random accesspreamble signal transmitted by the UE is one SC-FDMA symbol or one OFDMsymbol, thus air interface overhead of random access can be greatlyreduced on a premise that a UE in a small cell (Small Cell) can accessthe small cell randomly. Besides, the design of the PRACH may be morecompatible with existing systems, and especially, it is not necessary tointroduce a new limitation on PUSCH transmission and a new design on thesize of a PUSCH transmission block.

FIG. 8 is a schematic structural diagram of a network side deviceaccording to another embodiment of the present disclosure. As shown inFIG. 8, the network side device may include a transmitter 81, a receiver82, a memory 83 and a processor 84 which is coupled with the transmitter81, the receiver 82 and the memory 83 respectively. Certainly, thenetwork side device may further include general parts, such as anantenna and/or an input-output device and etc, which are not limitedhere in the embodiment of the present disclosure.

The memory 83 stores a series of program codes, and the processor 84 isconfigured to call the program codes stored in the memory 83 to executefollowing operations:

receiving, via the receiver 82, a random access preamble signaltransmitted by a UE, where duration of the random access preamble signalis one SC-FDMA symbol or one OFDM symbol;

transmitting, via the transmitter 81, a random access response to theUE.

It should be noted that the network side device shown in FIG. 8 may beused to implement the method provided by the embodiment shown in FIG. 3of the present disclosure, and descriptions about the random accesspreamble signal and a signaling, and a PRACH resource band or resourceband pair are all the same as those in the method embodiment, which willnot be repeated herein.

In this embodiment, the network side device refers to a node sendingdata on a downlink channel, such as a base station. For a D2D system,the network side device may be a UE, namely a UE sending data to anotherUE on the downlink channel.

In the aforementioned embodiment, the duration of the random accesspreamble signal transmitted by the UE is one SC-FDMA symbol or one OFDMsymbol, thus air interface overhead of random access can be greatlyreduced on a premise that a UE in a small cell (Small Cell) can accessthe small cell randomly. Besides, the design of the PRACH may be morecompatible with existing systems, and especially, it is not necessary tointroduce a new limitation on PUSCH transmission and a new design on thesize of a PUSCH transmission block.

FIG. 9 is a schematic structural diagram of a user equipment accordingto another embodiment of the present disclosure. As shown in FIG. 9, theuser equipment may include a transmitter 91, a receiver 92, a memory 93and a processor 94 which is coupled with the transmitter 91, thereceiver 92 and the memory 93 respectively. Certainly, the userequipment may further include general parts, such as an antenna and/oran input-output device and etc, which are not limited here in theembodiment of the present disclosure.

The memory 93 stores a series of program codes, and the processor 94 isconfigured to call the program codes stored in the memory 93 to executefollowing operations:

generating a random access preamble signal, where duration of the randomaccess preamble signal is one single carrier frequency division multipleaccess SC-FDMA symbol or one orthogonal frequency division multiplexingOFDM symbol;

transmitting, via the transmitter 91, the random access preamble signalto a network side device;

receiving, via the receiver 92, a random access response transmitted bythe network side device.

It should be noted that the user equipment shown in FIG. 9 may be usedto implement the method provided by the embodiment shown in FIG. 4 ofthe present disclosure, and descriptions about the random accesspreamble signal and a signaling, and a PRACH resource band or resourceband pair are all the same as those in the method embodiment, which willnot be repeated herein.

In the aforementioned embodiment, the duration of the random accesspreamble signal transmitted by the UE is one SC-FDMA symbol or one OFDMsymbol, thus air interface overhead of random access can be greatlyreduced on a premise that a UE in a small cell (Small Cell) can accessthe small cell randomly. Besides, the design of the PRACH may be morecompatible with existing systems, and especially, it is not necessary tointroduce a new limitation on PUSCH transmission and a new design on thesize of a PUSCH transmission block.

People skilled in the art may understand that an accompanying drawing isonly a schematic view of an optional embodiment, the module or the flowin the accompanying drawing is not necessary for implementing thepresent disclosure.

Persons skilled in the art may understand that modules in the devices ofthe embodiments may distribute in the devices of the embodimentsaccording to the descriptions of the embodiments, or locate in one ormore devices other than the present embodiments via performingcorresponding changes. The modules in the aforementioned embodiments maybe combined into one module, or further be divided into a plurality ofsub-modules.

Finally, it should be noted that the foregoing embodiments are merelyintended for describing the technical solutions of the presentdisclosure other than limiting the present disclosure. Although thepresent disclosure is described in detail with reference to theforegoing embodiments, a person of ordinary skill in the art shouldunderstand that he may still make modifications to the technicalsolutions described in the foregoing embodiments, or make equivalentreplacements to some technical features thereof; however thesemodifications or replacements will not cause the essence ofcorresponding technical solutions to depart from the scope of thetechnical solutions of the embodiments of the present disclosure.

What is claimed is:
 1. A radio communication method, comprising:receiving, by a network side device, a random access preamble signaltransmitted by a user equipment, wherein a duration of the random accesspreamble signal is one single carrier frequency division multiple access(SC-FDMA) symbol or one orthogonal frequency division multiplexing(OFDM) symbol; generating, by the network side device, a random accessresponse according to the random access preamble signal; andtransmitting the random access response to the user equipment.
 2. Themethod according to claim 1, before the receiving, by a network sidedevice, a random access preamble signal transmitted by a user equipment,further comprising: transmitting, by the network side device, asignaling to the user equipment, wherein the signaling indicates thatthe duration of the random access preamble signal currently used by theuser equipment is one SC-FDMA symbol or one OFDM symbol.
 3. The methodaccording to claim 2, wherein the network side device is a base stationof a small cell, and wherein the method further includes: before thetransmitting, by the network side device, a signaling to the userequipment, determining, by the network side device, that the userequipment does not need to execute uplink time synchronization.
 4. Themethod according to claim 1, wherein before the receiving, by a networkside device, a random access preamble signal transmitted by a userequipment, further comprising: determining, by the network side device,a sequence group number and a base sequence number of the random accesspreamble signal, wherein the determined sequence group number isconsistent with a sequence group number of a sounding reference signalor a physical uplink shared channel demodulation reference signal, andthe determined base sequence number is consistent with a base sequencenumber of the sounding reference signal or the physical uplink sharedchannel demodulation reference signal; and transmitting, by the networkside device, the determined sequence group number and the determinedbase sequence number to the user equipment.
 5. The method according toclaim 1, wherein before the receiving, by a network side device, arandom access preamble signal transmitted by a user equipment, furthercomprising: determining, by the network side device, a symbol thatcarries a physical random access channel (PRACH) resource band orresource band pair of the random access preamble signal in a subframe,wherein for a frequency division duplexing system, the symbol is a lastone SC-FDMA symbol or OFDM symbol in an uplink subframe, or, for a timedivision duplexing system, the symbol is a last one or last two SC-FDMAsymbols or OFDM symbols in an uplink subframe or a special subframe. 6.The method according to claim 1, wherein the random access response doesnot comprise timing alignment information.
 7. A network side device,comprising: a receiving module, configured to receive a random accesspreamble signal transmitted by a user equipment, wherein a duration ofthe random access preamble signal is one single carrier frequencydivision multiple access (SC-FDMA) symbol or one orthogonal frequencydivision multiplexing (OFDM) symbol; a processing module, configured togenerate a random access response according to the random accesspreamble signal received by the receiving module; and a transmittingmodule, configured to transmit the random access response generated bythe processing module to the user equipment.
 8. The network side deviceaccording to claim 7, wherein the processing module is furtherconfigured to transmit a signaling via the transmitting module to theuser equipment, wherein the signaling indicates that the duration of therandom access preamble signal currently used by the user equipment isone SC-FDMA symbol or one OFDM symbol.
 9. The network side deviceaccording to claim 8, wherein the network side device is a base stationof a small cell, and, the processing module is further configured to,before the transmitting module transmits the signaling to the userequipment, determine that the user equipment does not need to executeuplink time synchronization.
 10. The network side device according toclaim 7, wherein the processing module is further configured todetermine a sequence group number and a base sequence number of therandom access preamble signal, wherein the determined sequence groupnumber is consistent with a sequence group number of a soundingreference signal or a physical uplink shared channel demodulationreference signal, and the determined base sequence number is consistentwith a base sequence number of the sounding reference signal or thephysical uplink shared channel demodulation reference signal; and thetransmitting module is further configured to transmit the sequence groupnumber and the base sequence number determined by the processing moduleto the user equipment.
 11. The network side device according to claim 7,wherein the processing module is further configured to determine asymbol configured to carry a physical random access channel (PRACH)resource band or resource band pair of the random access preamble signalin a subframe, and for a frequency division duplexing system, the symbolis a last one SC-FDMA symbol or OFDM symbol in an uplink subframe, or,for a time division duplexing system, the symbol is a last one or lasttwo SC-FDMA symbols or OFDM symbols in an uplink subframe or a specialsubframe.
 12. The network side device according to claim 7, wherein therandom access response transmitted by the transmitting module does notcomprise timing alignment information.
 13. A user equipment, comprising:a generating module, configured to generate a random access preamblesignal, wherein a duration of the random access preamble signal is onesingle carrier frequency division multiple access (SC-FDMA) symbol orone orthogonal frequency division multiplexing (OFDM) symbol; atransmitting module, configured to transmit the random access preamblesignal generated by the generating module to a network side device; anda receiving module, configured to, after the transmitting moduletransmits the random access preamble signal, receive a random accessresponse transmitted by the network side device.
 14. The user equipmentaccording to claim 13, wherein the receiving module is furtherconfigured to receive a signaling transmitted by the network sidedevice, wherein the signaling indicates that the duration of the randomaccess preamble signal currently used by the user equipment is oneSC-FDMA symbol or one OFDM symbol; and the generating module is furtherconfigured to generate the random access preamble signal according tothe signaling received by the receiving module.
 15. The user equipmentaccording to claim 14, wherein the user equipment is located in a smallcell; and, the signaling received by the receiving module is transmittedafter the network side device determines that the user equipment doesnot need to execute uplink time synchronization.
 16. The user equipmentaccording to claim 13, further comprising: a determining module; whereinthe receiving module is further configured to, before the transmittingmodule transmits the random access preamble signal to the network sidedevice, receive information about a physical random access channel(PRACH) resource band or resource band pair used to carry the randomaccess preamble signal of the user equipment, wherein the information istransmitted by the network side device and the information comprises: atransmission period of the PRACH resource band or resource band pair, atransmission offset of the PRACH resource band or resource band pair ineach transmission period, and a frequency domain position of the PRACHresource band or resource band pair; the determining module isconfigured to, before the transmitting module transmits the randomaccess preamble signal to a network side device, determine, according tothe information about the PRACH resource band or resource band pair, aPRACH configured to carry the random access preamble signal of the userequipment; and the transmitting module is configured to transmit therandom access preamble signal generated by the generating module to thenetwork side device on the PRACH determined by the determining module.17. The user equipment according to claim 13, wherein the receivingmodule is further configured to, before the transmitting moduletransmits the random access preamble signal to a network side device,receive a sequence group number and a base sequence number of the randomaccess preamble signal that are transmitted by the network side device;wherein, the sequence group number is consistent with a sequence groupnumber of a sounding reference signal or a physical uplink sharedchannel demodulation reference signal, and the base sequence number isconsistent with a base sequence number of the sounding reference signalor the physical uplink shared channel demodulation reference signal; andthe generating module is configured to generate, according to thesequence group number received by the receiving module and the basesequence number received by the receiving module, the random accesspreamble signal.
 18. The user equipment according to claim 13, furthercomprising: a determining module; wherein the determining module isconfigured to determine a symbol configured to carry a physical randomaccess channel (PRACH) resource band or resource band pair of the randomaccess preamble signal in a subframe, and for a frequency divisionduplexing system, the symbol is a last one SC-FDMA symbol or OFDM symbolin an uplink subframe; or, for a time division duplexing system, thesymbol is a last one or last two SC-FDMA symbols or OFDM symbols in anuplink subframe or a special subframe; and the transmitting module isconfigured to transmit the random access preamble signal generated bythe generating module to the network side device on the SC-FDMA symbolor the OFDM symbol determined by the determining module in the subframe.19. The user equipment according to claim 13, further comprising: adetermining module; wherein the determining module is configured to,before the transmitting module transmits the random access preamblesignal to the network side device, determine that the random accesspreamble signal adopts a mapping manner with one subcarrier interval ina frequency domain; the receiving module is further configured toreceive a transmission comb of the random access preamble signaltransmitted by the network side device; and the transmitting module isconfigured to transmit the random access preamble signal on a subcarrierindicated by the transmission comb received by the receiving module. 20.The user equipment according to claim 13, wherein the random accessresponse received by the receiving module does not comprise timingalignment information; and the transmitting module is further configuredto, after the receiving module receives a random access responsetransmitted by the network side device, perform uplink datatransmission, and during the transmission, according to the randomaccess response, not adjust a transmission time of the uplink data.